Part 4 Systems and components Chapter 7 Pressure equipment · 2018. 1. 3. · P a r t 4 C h a p t e...

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DNV GL AS

RULES FOR CLASSIFICATION

Ships

Edition January 2018

Part 4 Systems and components

Chapter 7 Pressure equipment

FOREWORD

DNV GL rules for classification contain procedural and technical requirements related to obtainingand retaining a class certificate. The rules represent all requirements adopted by the Society asbasis for classification.

© DNV GL AS January 2018

Any comments may be sent by e-mail to [email protected]

If any person suffers loss or damage which is proved to have been caused by any negligent act or omission of DNV GL, then DNV GL shallpay compensation to such person for his proved direct loss or damage. However, the compensation shall not exceed an amount equal to tentimes the fee charged for the service in question, provided that the maximum compensation shall never exceed USD 2 million.

In this provision "DNV GL" shall mean DNV GL AS, its direct and indirect owners as well as all its affiliates, subsidiaries, directors, officers,employees, agents and any other acting on behalf of DNV GL.

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Rules for classification: Ships — DNVGL-RU-SHIP Pt.4 Ch.7. Edition January 2018 Page 3Pressure equipment

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CHANGES – CURRENT

This document supersedes the January 2017 edition of DNVGL-RU-SHIP Pt.4 Ch.7.Changes in this document are highlighted in red colour. However, if the changes involve a whole chapter,section or sub-section, normally only the title will be in red colour.

Changes January 2018, entering into force 1 July 2018.Topic Reference Description

Harmonisation of hydraulicpressure test requirements forvalves / equipment of boilers

Sec.7 [4.6.7] Procedure for the testing of equipment, valves and fittings withdesign temperature above 120°C specified.

Sec.4 [6.4.1]Inconsistent thicknessrequirements for nozzles andbranches Sec.4 [6.4.2]

Sec.4 [6.4.1] separated in Sec.4 [6.4.1] for general wallthickness and Sec.4 [6.4.2] for taking additional loads intoaccount.

Inconsistency of minimum wallthickness requirements

Sec.4 [2.6.1] and[2.6.2]

— Sec.4 [2.6.1]: minimum thickness of shells and dished endscompleted by requirements for stainless steel and non-ferrous materials. Requirements for type C independenttanks and process pressure vessels according to IGC added.

— Sec.4 [2.6.2]: deleted.

Reinforcing plates for supports Sec.4 [2.3.2] Loads for installation and support that shall considered for thedesign of the pressure equipment.

Requirements for materialtesting

Sec.1 [3.2.2] Guidance note added for material certification of parts directlywelded to pressurised parts of the pressure equipment.

UT Testing for plates Sec.7 [4.1.4] Ultrasonic testing for flat plates loaded by residual weldingstress specified.

Sec.1 [1.1.2] Expression "including mountings" deleted for pressure vessels,because it is covered by the scope of Ch.6. Term "mountings"modified to "equipment, valves and fittings" and added also tothermal oil heaters.

Sec.1 Table 8 Table created for certification requirements for equipment,valves and fittings.

Sec.3 [3.2.2] Requirement for drenching system restored.

Sec.4 [2.5.2] Calculation of the nominal design stress for austenitic stainlesssteels modified from specified minimum lower yield stress atdesign material temperature to 1.0% proof stress at designmaterial temperature.

Sec.4 [3.5.2] Expression "open feed water system" modified to system"without adequate feed water treatment and degassing".

Sec.4 [4.1.1] Explanation for 's' modified to "minimum plate thickness afterforming" and "calculated thickness" modified to "minimum platethickness after forming" in the text.

Other changes

Sec.4 [4.1.4] Explanation for 's' modified to "minimum plate thickness afterforming".

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Topic Reference Description

Sec.4 [4.2.4] Last sentence in Sec.4 [4.2.2] deleted and new para addedregarding the thickness of the cylindrical parts of dished ends.

Sec.4 [6.6.1] Use of the calculation of openings extended to stayed andunstayed flat plates.

Sec.4 [7] Heading made more generic to cover the calculations of firedand unfired cylindrical shells under external pressure.

Sec.5 [1.1.3] Term "mounting" modified to "equipment, valves and fittings".

Sec.5 [2.1] Location for the installation of safety valves at steam boilersadded.

Sec.6 Table 2 For "salinity high" and "oil content high" "shut-down of feedwater pump" has been modified to 'interruption of feed watersupply' and monitoring is only necessary if contamination withsalt or oil is possible.

Sec.7 [4.4.3] Procedure for WPT of circumferential welding seams specified.

App.A [2] Number, type and location of inspection openings mademandatory.

Editorial correctionsIn addition to the above stated changes, editorial corrections may have been made.

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CONTENTS

Changes – current.................................................................................................. 3

Section 1 General requirements............................................................................101 Classification......................................................................................10

1.1 Application..................................................................................... 101.2 Cross-references............................................................................. 10

2 Definitions..........................................................................................112.1 Terms............................................................................................ 112.2 Specifications................................................................................. 112.3 Symbols.........................................................................................132.4 Units............................................................................................. 172.5 Pressure equipment classes............................................................. 17

3 Documentation...................................................................................193.1 Documentation requirements............................................................193.2 Certification requirements................................................................ 21

4 Accumulators for hydraulic systems.................................................. 254.1 Design........................................................................................... 254.2 Fabrication..................................................................................... 264.3 Certification....................................................................................26

5 Gas cylinders for fixed fire extinguishing systems.............................265.1 General..........................................................................................265.2 Design........................................................................................... 265.3 Fabrication..................................................................................... 265.4 Certification....................................................................................26

6 Operating instructions and signboards.............................................. 276.1 General..........................................................................................27

Section 2 Materials................................................................................................281 Material requirements........................................................................28

1.1 General..........................................................................................281.2 Boilers and pressure vessels............................................................ 281.3 Thermal-oil heaters......................................................................... 29

Section 3 Arrangement..........................................................................................301 General.............................................................................................. 30

1.1 Access and inspection openings........................................................ 301.2 Draining and venting.......................................................................30

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1.3 Positioning..................................................................................... 301.4 Marking......................................................................................... 31

2 Boilers................................................................................................322.1 Instruments................................................................................... 322.2 Positioning..................................................................................... 322.3 Exhaust gas boiler or economisers....................................................32

3 Components and equipment in thermal-oil installations.................... 333.1 General..........................................................................................333.2 Heaters..........................................................................................333.3 Expansion tank...............................................................................343.4 Pre-pressurised systems.................................................................. 353.5 Safety arrangements....................................................................... 353.6 Control and monitoring system.........................................................353.7 Insulation and shielding...................................................................35

4 Oil burner and oil firing equipment................................................... 354.1 General..........................................................................................354.2 Fuel oil supply................................................................................364.3 Combustion air supply.....................................................................364.4 Exhaust gas ducting........................................................................374.5 Marking......................................................................................... 37

Section 4 General design requirements................................................................ 381 General.............................................................................................. 38

1.1 Application..................................................................................... 382 Design criteria................................................................................... 39

2.1 Design pressure..............................................................................392.2 Calculating pressure........................................................................392.3 Other loadings................................................................................402.4 Design material temperature............................................................402.5 Nominal design stress..................................................................... 412.6 Minimum thickness of shells and dished ends..................................... 432.7 Corrosion allowance........................................................................ 442.8 Tolerance and fabrication allowance.................................................. 442.9 Joint efficiency................................................................................44

3 Shells, headers and tubes..................................................................453.1 Conditions......................................................................................453.2 Cylindrical shells............................................................................. 453.3 Spherical shells...............................................................................463.4 Conical shells of circular sections......................................................46

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3.5 Tubes subjected to internal pressure................................................. 503.6 Tubes subjected to external pressure................................................ 503.7 Heat exchanger tubes..................................................................... 513.8 Scantlings of boiler shells with set in end plates................................. 523.9 Efficiency of ligaments between tube holes........................................ 523.10 Compensating effect of tube stubs.................................................. 57

4 Dished ends....................................................................................... 584.1 Conditions......................................................................................584.2 Dished ends for vertical boiler fireboxes............................................ 64

5 Flat end plates...................................................................................655.1 General..........................................................................................655.2 Un-stayed flat end plates.................................................................665.3 Scantlings of flat plates supported by stays....................................... 695.4 Tube plates with stay tubes and tubes within tube nests...................... 705.5 Covers for inspection openings and manholes.....................................755.6 Straps and girders.......................................................................... 76

6 Openings and compensations............................................................ 786.1 General..........................................................................................786.2 Openings not requiring reinforcement................................................786.3 Openings requiring reinforcement..................................................... 796.4 Minimum thickness of nozzles and branches.......................................826.5 Welded branch connections.............................................................. 826.6 Openings in flat plates.................................................................... 89

7 Fired and unfired cylindrical shells under external pressure............. 907.1 Plain cylindrical shells......................................................................907.2 Corrugated furnaces........................................................................947.3 Stiffeners....................................................................................... 947.4 Fireboxes for vertical boilers............................................................ 957.5 Openings in furnaces.......................................................................967.6 Internal uptakes in vertical boilers.................................................... 96

8 Stays..................................................................................................978.1 Stay tubes and bar stays.................................................................978.2 Gusset stays.................................................................................. 98

Section 5 Equipment, valves and fittings...........................................................1001 General............................................................................................ 100

1.1 Construction................................................................................. 1002 Safety valves................................................................................... 100

2.1 Valves on boilers...........................................................................100

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2.2 Valves on pressure vessels other than boilers and on steam-heatedsteam generators............................................................................... 1022.3 Protection of condensers against overpressure.................................. 103

3 Stop valves and check valves.......................................................... 1033.1 Valves on boilers...........................................................................1033.2 Valves on pressure vessels other than boilers and steam-heatedsteam generators............................................................................... 104

4 Blow-down valves and test valves for boiler water..........................1044.1 Blow-down valves......................................................................... 1044.2 Test valves................................................................................... 104

5 Gauges............................................................................................. 1045.1 Water gauges............................................................................... 1045.2 Pressure gauges........................................................................... 105

Section 6 Instrumentation and automation........................................................ 1061 General............................................................................................ 106

1.1 Cross reference.............................................................................1061.2 Manual operation.......................................................................... 106

2 Pressure vessels.............................................................................. 1072.1 Monitoring.................................................................................... 107

3 Boilers..............................................................................................1073.1 Automatic control..........................................................................1073.2 Monitoring.................................................................................... 107

4 Exhaust gas boilers or economisers................................................ 1084.1 Instruments and Monitoring........................................................... 108

5 Water heaters..................................................................................1095.1 Monitoring.................................................................................... 109

6 Thermal-oil Heaters......................................................................... 1096.1 Automatic control..........................................................................1096.2 Monitoring.................................................................................... 1096.3 Indicators.....................................................................................110

7 Oil burners.......................................................................................1117.1 General........................................................................................1117.2 Automatic quick-closing valves........................................................1117.3 Safety time.................................................................................. 1117.4 Monitoring.................................................................................... 112

Section 7 Manufacture, workmanship and testing.............................................. 1141 Manufacture.....................................................................................114

1.1 General........................................................................................114

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2 Workmanship...................................................................................1142.1 Cutting of plates........................................................................... 1142.2 Welded joints................................................................................1142.3 Tolerances for shells...................................................................... 1162.4 Fitting of tubes............................................................................. 1162.5 Doors and plugs........................................................................... 117

3 Heat treatment................................................................................ 1173.1 Post-weld heat treatment...............................................................1173.2 Heat treatment of plates after hot or cold forming.............................1183.3 Heat treatment of tubes after bending.............................................119

4 Testing............................................................................................. 1194.1 Extent of non-destructive testing.................................................... 1194.2 Performance of non-destructive testing............................................ 1204.3 Acceptance criteria for non-destructive testing and repair of defects.....1214.4 Welding production test................................................................. 1224.5 Constructional check......................................................................1254.6 Hydraulic test............................................................................... 1254.7 Performance test...........................................................................126

Appendix A Types and minimum dimensions of the inspection openings inpressure equipment............................................................................................127

1 Definitions and dimensions..............................................................1271.1 Examination holes......................................................................... 1271.2 Manholes......................................................................................127

2 Locations..........................................................................................1272.1 Inspection openings.......................................................................127

Changes – historic.............................................................................................. 129

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SECTION 1 GENERAL REQUIREMENTS

1 Classification

1.1 Application

1.1.1 Pressure equipment according to these rules are components subject to gaseous or liquid fluids with apressure above 0.5 bar. Pressure equipment may consist of more than one pressurized compartment.

1.1.2 The term pressure equipment in this section applies to the following components:

— pressure vessels necessary for performing the main functions listed in Pt.1 Ch.1 Sec.1 [1.2]— other pressure vessels containing:

— harmful fluids (toxic or corrosive)— fluids with flash point below 100°C— fluids with temperature above 220°C— fluids with pressure above 40 bar— compressed gases where

pd × V ≥1500 bar ltr— boilers and hot water generators, including equipment, valves and fittings

— thermal-oil heaters, including equipment, valves and fittings

— oil burners and oil firing equipment.pd = design pressureV = volume.

1.1.3 Pressure equipment according to [1.1.2] are subject to certification by the Society.

1.1.4 The control and monitoring systems shall be certified according to Ch.9 for the following:

— electrically heated pressure vessels— boilers— thermal-oil heaters— hot and warm water generators— oil burners and oil firing equipment.

1.2 Cross-references

1.2.1 Pressure equipment for liquefied gases shall meet the requirements in Pt.5 Ch.7 Sec.5.Cargo process pressure vessels, as defined in Pt.5 Ch.7 Sec.1, shall be graded as class I pressure equipment.However, the selections of materials, qualification of welding procedures and production weld tests shallbe according to the rules for classification of ships Pt.5 Ch.7 Sec.5 and Sec.6. Non-cargo process pressurevessels, as defined in the rules for classification of ships Pt.5 Ch.7 Sec.1, shall meet the requirements ofCh.7.Boiler installations on liquefied gas carriers with gas operated machinery shall meet the requirements in therules for classification of ships Pt.5 Ch.7 Sec.16

1.2.2 Pressure vessels for refrigerating plants shall, in addition to the requirements in this section, meet therequirements of the rules for classification of ships Pt.6 Ch.4 Sec.10 and Ch.6 Sec.6.

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2 Definitions

2.1 Terms

2.1.1 A boiler is defined as a welded pressure equipment:

— In which steam is generated by the application of heat from oil or gas burners, coal, exhaust gases etc.with a pressure above atmospheric pressure (steam generator) – the generated steam shall be used in asystem outside of the steam generator.

— In which the temperature of water is raised to a temperature of >120°C at the discharge side (hot watergenerator) – the generated hot water shall be used in a system outside of the hot water generator.

Superheaters, economisers, re-heaters and other pressure parts including valves and fittings, connecteddirectly to the boiler without intervening valves, shall be considered as parts of the boiler.

2.1.2 A thermal-oil heater is defined as an arrangement in which organic fluids (thermal-oils) are heated byoil or gas burners, exhaust gases or electricity to a temperature below the initial boiling point at atmosphericpressure and circulated for the purpose of heating fuel oil, or cargo, or for production of steam or hot waterfor auxiliary purposes.

2.1.3 A warm water generator is defined as an arrangement in which the temperature of the water is raisedto a temperature of ≤120°C at the discharge side of the generator. Warm water generators are considered aspressure vessels.

2.1.4 A steam heated steam generator is a heat exchanger heated by steam with higher pressure/temperature for the production of steam at lower pressure/temperature. Steam heated steam generators arenot endangered by overheating and are considered as pressure vessels.

2.1.5 Oil burners and oil firing equipment are used for burning liquid or gaseous fuels. They may be installedon propulsion boilers, auxiliary boilers, thermal-oil heaters, hot or warm water generators as well as inert gasgenerators.

2.1.6 Pressure is the pressure relative to atmospheric pressure, i.e. the gauge pressure. As a consequence,vacuum pressure is designated by a negative value.

2.1.7 The maximum allowable working pressure (MAWP) is the maximum pressure which may be safely heldin normal operation of the pressure equipment.

2.1.8 The thermal oil temperature is the temperature of the thermal oil in the centre of the flow cross-section.

2.1.9 The film temperature is the wall temperature on the thermal oil side. In the case of heated surfaces,this may differ considerably from the temperature of the thermal oil.

2.1.10 The discharge temperature is the temperature of the fluid immediately at the heater outlet.

2.1.11 The return temperature is the temperature of the fluid immediately at the heater inlet,

2.2 Specifications

2.2.1 In once-through forced flow boilers, the design pressure is the pressure at the superheater outlet or, inthe case of continuous flow boilers without a superheater, the steam pressure at the steam generator outlet.

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2.2.2 The heating surface is that part of the boiler walls through which heat is supplied to the system, i.e.:

— the area [m2] measured on the side exposed to fire or heating gas, or— in the case of electrical heating, the equivalent heating surface:

where:

H =heating surface

P =electric power

2.2.3 The sensor initiating a burner cut-off (BCO) shall be located at the low-low water level (LLWL).LLWLshall be at least 150 mm above the highest flue also when the ship heels 4° to either side.The highest flue (HF) shall remain wetted even when the ship is at the static heeling angles laid down inCh.1.The height of the water level is crucial to the response of the water level limiters.The dropping time is the time taken by the water level under conditions of interrupted feed and allowablesteam production, to drop from the low low water level (LLWL) to the level of the highest flue.

where:

Ds = allowable steam output

T = dropping time

v’ = specific volume of water at saturation temperature

V = Volume

The low low water level (LLWL) shall be set so that the dropping time is not less than 5 minutes.

2.2.4 The highest flue (HF) is the highest point on the side of the heating surface which is in contact with thewater and which is exposed to flame radiation. HF shall be defined by the boiler manufacturer in such a waythat, after shut-down of the burner from full-load condition or reduction of the heat supply from the engine,the flue gas temperature or exhaust gas temperature respectively is reduced to a value below 400 °C at thelevel of the highest flue. This shall be achieved before, in case of interrupted feed water supply, the waterlevel has dropped from the low low water level (LLWL) to a level 50 mm above HF.The highest flue on water tube boilers with an upper steam drum is the top edge of the highest gravity tubes.The requirements relating the highest flue do not apply to:

— water tube boiler risers up to 102 mm outer diameter— once-through forced flow boilers— superheaters— flues and exhaust gas heated parts in which the temperature of the heating gases does not exceed 400°C

at maximum continuous power.

The heat accumulated in furnaces and other heated boiler parts shall not lead to any inadmissible lowering ofthe water level due to subsequent evaporation when the oil burner is switched-off.This requirement to an inadmissible lowering of the water level is met for example, if it has beendemonstrated by calculation or trial that, after shut-down of the burner from full-load condition or reductionof the heat supply from the engine, the flue gas temperature or exhaust gas temperature respectively isreduced to a value below 400°C at the level of the highest flue, before, in case of interrupted feed water

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supply, the water level has dropped from the low low water level (LLWL) to a level 50 mm above the highestflue (HF).The water level indicators shall be arranged in such a way that the distance measured are 50 mm above HF.

2.3 Symbols

2.3.1 The symbols used are as given below in addition to those specifically stated in the relevant sections.

Table 1 Symbols

Symbol Description Unit

a major dimension of elliptical or rectangular unsupported area mm

ap diagonal pitch of holes projected on longitudinal axis mm

ao diminution for calculation of out-of-roundness mm

avmost probable largest combined vertical acceleration in 108 wave encounters(probability levelQ = 10-8) -

A area of reinforcement mm²

Ac compensating area for tube stubs mm²

Ap area supported by a stay mm²

Ax compensating area mm²

Aσ sectional area of a stay mm²

A1 sectional area of the stub projecting inside the shell mm²

A2 sectional area of fillet welds attaching the stub to the inside and outside of the shell mm²

A3 aggregate area of the orifice (safety valve – saturated steam) mm²

A4 aggregate area of the orifice (safety valve – superheated steam) mm²

b minor dimension of elliptical or rectangular unsupported area mm

bp diagonal pitch of holes projected circumferentially mm

BCO Burner cut-off -

c corrosion allowance mm

c1 constructional allowance mm

C factor depending on the method of supports -

d diameter of tube hole or opening mm

da mean inner diameter of the two openings mm

dc calculation diameter of openings/tube holes mm

de diameter of the largest circle passing through points of support mm

diinternal diameter of an opening or branch for a circular opening or the chord length in theplane being considered for elliptical or non-circular openings mm

dk root diameter of thread mm

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do outer diameter of the branch or tube mm

dp mean effective diameter of tube hole (efficiency of ligament) mm

ds shank diameter of a necked-down bolt mm

D nominal diameter mm

Db mean sealing or bolt pitch circle diameter mm

Di internal diameter mm

Dm mean diameter of plain furnace mm

Dmax maximum mean diameter of the furnace mm

Dmin minimum mean diameter of the furnace mm

Do outside diameter mm

Ds allowable steam output kg/h

DC internal diameter at the large end of the cone mm

DO outside diameter of the conical section mm

e efficiency of ligament -

eg distance between center lines of girders mm

ei breadth of jointing surface (inspection openings) mm

E modulus of elasticity N/mm²

fG coefficient for the calculation of gusset stays -

Fg load carried by one girder or gusset stay N

FB force imposed on bolted connection by working pressure N

FD force to close seal under service condition N

FD0 force to close seal in assembled condition N

FS total load on bolted connection in service N

F’S total load on bolted connection at test pressure N

FS0 total load on bolted connection in assembled condition with no pressure exerted N

FZ additional force due to loaded condition in connected piping N

g0 standard acceleration of gravity (9.81 m/s²) m/s²

h vertical distance from load point to top of pressure equipment m

hd height of cylindrical portion of dished end mm

hg height of girder or gusset stay mm

H heating surface m²

Hd outside height of curvature of dished end mm

HWL high water level (alarm) -

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Ix second moment of area Nmm²

k calculation factor for reinforced openings in spherical, cylindrical and conical shells -

kf calculation factor for flat end plates -

k0 sealing factor for assembled condition mm

k1 sealing factor for service condition mm

K factor depending on the number of supports -

KC factor taking into account the stress in the junction (conical shells) -

KD sealing material deformation factor N/mm²

KS factor for calculating the aggregate area of orifice for safety valves -

l free length between girder supports mm

lb supporting length of the branch at openings mm

l’b supporting length of the internal branch projection at openings mm

ls supporting length of the shell at openings mm

L calculation length (conical section and furnace) mm

Lb calculation length at the branch (openings) mm

Ls calculation length at the shell (openings) mm

LLWL low low water level (lowest specified water level, burner cut-off (BCO)) -

LWL low water level (alarm) -

M bending moment acting on girder at given load Nmm

MC factor for calculating conical shells -

n number of bolts forming a connection -

nw integral number of waves -

NWL normal water level -

p pressure bar

pc calculating pressure bar

pd design pressure bar

pt test pressure bar

P electric power kW

r inside knuckle radius of tori-spherical ends mm

ri inside radius of transition knuckle (conical shell) mm

r1 radius of the flanging at dished ends with openings mm

R inside radius of spherical part of tori-spherical ends mm

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ReHspecified minimum upper yield stress at room temperature. If the stress-strain curve doesnot show a defined yield stress, the 0.2% proof stress shall be applied N/mm

2

Rm specified minimum tensile strength at room temperature N/mm2

Rmt specified minimum tensile strength at design material temperature N/mm2

Retspecified minimum lower yield stress at design material temperature. If the stress-straincurve does not show a defined yield stress, the 0.2% proof stress shall be applied N/mm

2

Rm,100 000 average stress to produce rupture in 100 000 hours at design material temperature N/mm2

Rp1.0 1.0% proof stress N/mm2.

s thickness mm

sa actual thickness of the flat plate as built minus corrosion allowance mm

sb thickness of the branch mm

sba thickness of the branch as built minus corrosion allowance mm

sg thickness of girder mm

sm minimum wall thickness of tube stub as calculated without corrosion allowance mm

sp pitch of tubes mm

sp1 the shorter of any two adjacent pitches mm

sp2 the longer of any two adjacent pitches mm

sr required thickness at the junction of the cone and the cylinder mm

ss thickness of the shell as calculated mm

ssa actual thickness of the shell as built minus corrosion allowance mm

s1 thickness of cylindrical shell as calculated mm

s2 thickness of end plate as calculated at the junction with the shell mm

S safety factor -

SK safety factor against elastic instability -

td design temperature °C

tD temperature difference between saturated and superheated steam °C

T dropping time sec

u percentage of out of roundness %

v joint efficiency -

v’ specific volume of water at saturation temperature m³/kg

V Volume (including its attachments up to the first detachable connection or up to the weldingseam connecting the nozzle of the pressure equipment to the piping system) m³ or ltr

W section modulus of one girder mm³

X area requiring compensation at flat end plates (opening) mm²

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X1 coefficient considering shell and end plate thickness -

y factor depending on the ratio b/a -

yi factor depending on the ratio b/a for calculating inspection openings -

Y area of reinforcement at flat end plates (openings) mm²

z coefficient for section modulus -

α C half apex angle of the section (conical shells) °

α p angle of centre line of cylinder to the centre line of diagonal holes °

α angle of gusset stay to longitudinal axis of the shell °

β shape factor for dished ends -

ψ difference between angle of slope of the adjoining parts -

ρ density of the fluid t/m³

σt nominal design stress at design metal temperature N/mm2

ν Poisson's ratio -

2.4 Units

2.4.1 Unless otherwise specified the following units are used in this section:

— dimensions (lengths, diameters, thicknesses etc.): mm— areas: mm2 or m2 for heating surface H— pressures: bar— temperatures: °C— mechanical properties of materials (ultimate tensile strength, yield strength etc.): N/mm2

— impact energy: J— electric power: kW.

2.5 Pressure equipment classes

2.5.1 For rule purposes pressure equipment is graded in classes as shown in Table 2.

Table 2 Pressure equipment classes

Pressure equipment class I II III

Steam boilers pd > 3.5 pd ≤ 3.5 -

Thermal oil heaters

pd > 10

or

td > 300

pd ≤ 10

and

td ≤ 300

-

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Dust collectors, dust filters, bulk storage tanks

pd > 5

or

Do > 1000

pd ≤ 5

and

Do ≤ 1000

Operating fluids for pressure vessels

Liquefied gases (propane, butane, etc.),

flammable gases, harmful fluids (toxic orcorrosive)

all – –

Refrigerants (see Ch.6 Sec.6 [3.1]) Group 2 Group 1 –

Steam, compressed air, non-flammable gases

pd > 16

or

td > 300

pd ≤ 16

and

td ≤ 300

pd ≤ 7

and

td ≤ 170

Thermal oils

pd > 16

or

td > 300

pd ≤ 16

and

td ≤ 300

pd ≤ 7

and

td ≤ 150

Liquid fuels, lubricating oils,flammable hydraulic fluids

pd > 16

or

td > 150

pd ≤ 16

and

td ≤ 150

pd ≤ 7

and

td ≤ 60

Water, non-flammable hydraulic fluids

pd > 40

or

td > 300

pd ≤ 40

and

td ≤ 300

pd ≤ 16

and

td ≤ 200

Guidance note:For pressure equipment with more than one chamber where the chambers have different pressure equipment classes, theboundaries between the chambers have to fulfill the requirements of the higher class. The documentation of the pressureequipment should cover all chambers, even the chambers of pressure equipment class III.

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3 Documentation

3.1 Documentation requirements

3.1.1 Documentation shall be submitted as required by Table 3.

Table 3 Documentation requirements

Object Documentation type Additional description Info

C010 – Design criteria

— design pressure— design temperature— volume— fluid— additional loads (if applicable)— heating surface of heat exchanger and warm water

generator— heating power and discharge temperature of warm

water generator— proposed set pressure of safety valve— pressure equipment class

FI

C020 – Assembly orarrangement drawing Including valves and fittings. FI

C030 – Detailed drawing Cross sectional and plan views. Attachments andsupports. AP

C040 – Design analysis FI

Pressure vessel

C050 – Non-destructivetesting (NDT) plan FI


— design pressure— design temperature— volume— heating surface— estimated evaporation— proposed set pressure of safety valves— blow-off capacity of safety valves— pressure equipment class

FI


C030 – Detailed drawing Including attachments and supports. AP


C050 – NDT plan FI

I200 – Control and monitoringsystem documentation AP

Propulsion boiler

Z161—Operation manual FI

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— design pressure— design temperature— volume— heating surface— estimated evaporation— exhaust gas inlet and outlet temperature of

exhaust gas boiler— heating power and discharge temperature of hot

water generator— proposed set pressure of safety valves— blow-off capacity of safety valves— pressure equipment class

FI


C030 – Detailed drawing Including attachments and supports. AP


C050 – Non-destructivetesting (NDT) plan FI


Auxiliary boiler

Z161—Operation manual FI


— design pressure— design temperature— volume— heating surface— heating power— maximum discharge temperature— minimum flow rate— exhaust gas inlet and outlet temperature of

exhaust gas heated thermal oil heater— data for the applicable thermal oil

FI


C020 – Assembly orarrangement drawing

Fire extinguishing in the heater furnace and at theexhaust gas heated thermal oil heater. AP

C030 – Detailed drawing Cross sectional and plan views. AP

C040 – Design analysisCalculations of maximum film temperature in thefurnace tubes, in accordance with a recognizedstandard, e.g. DIN 4754.

FI, R

C050 – NDT plan FI


Thermal oil heater

Z161 – Operation manual FI

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C010 – Design criteria — heating power— fuels intended to be used.

FI

C020 – Assembly orarrangement drawing — AP

C030 – Detail drawing — burner internal piping diagram— list of equipment

AP

I200 – Control and monitoringsystem documentation — AP

Burners

Z161 – Operation manual

— description of heat generation plant— start-up and shut-down sequence— specification of safety times during start-up and

operation

FI

AP = For approval; FI = For information; R = On request

3.1.2 For general requirements for documentation, see Pt.1 Ch.3 Sec.2.

3.1.3 For a full definition of the documentation types, see Pt.1 Ch.3 Sec.3.

3.1.4 For class III pressure equipment intended for water and non-flammable hydraulic fluids,documentation needs not to be submitted if the temperature of the fluid is less than 95°C. In such cases,certification shall be based on visual inspection, review of materials certificates and pressure testingwitnessed by the surveyor.

Guidance note:Even though the drawings for pressure equipment class III intended for water and non-flammable hydraulic fluids with atemperature of the fluid less than 95°C need not to be submitted for drawing approval, this pressure equipment class III has tofulfill the requirements of this chapter.


3.1.5 Drawing approval of charge air coolers is not required. In respect to the requirements for inspection,testing and certification see Ch.3 Sec.1 Table 8.

3.2 Certification requirements

3.2.1 Requirements for manufacturers, material certificates, welding, testing and heat treatment for thedifferent pressure equipment classes are indicated in Table 4.

Table 4 Requirements for pressure equipment classes

Class

Approvedpressure

equipmentmanufacturer Sec.7 [1.1.1]

Approvedmaterial

manufacturer

Materialcertificates

Weldingprocedure

qualification Sec.7[1.1.2]

Non-destructive testing

Sec.7 [4.1]

Heattreatment

Visual anddimensionalinspection

Sec.7[4.5]

Hydraulictest Sec.7

[4.6]

I Required Required SeeTable 5 RequiredDepending on

joint efficiency v

SeeSec.7[3]

Required Required

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II Required Required SeeTable 6 RequiredDepending on

joint efficiency v

SeeSec.7[3]

Required Required

III SeeTable 7Depending on

joint efficiency v Required Required

3.2.2 Pressure equipment shall be certified as required by Table 5 to Table 10. For definition of the differenttypes of certificates see Pt.1 Ch.3 Sec.5.

Guidance note:For materials of parts not covered by higher requirements for material certification in Table 5 to Table 7 but directly welded topressurised parts of the pressure equipment, e.g. doubling plates at support feet, lifting lugs, TR material certificates may besufficient.


Table 5 Certification requirements for pressure equipment class I

Additional descriptionComponent Certificatetype Condition Dimension

Issued by Certificationstandard

Pressure equipment class I PC Society Rules

Plates, dished ends andheads MC Society Rules

Pipes and tubes (for shellsof pressure equipment andtubes of water tube boilers)

MC Society Rules

Stays, stay bolts and staytubes MC Society Rules

Smoke tubes (tubes subjectto external pressure) MC Manufacturer Rules

Tubes in heat exchanger andchannel plates in plate heatexchangers

MC Manufacturer Rules

Flanges, nozzles andbranches MC Manufacturer Rules

Manhole, headhole andhandhole closures MC Manufacturer Rules

Reinforcement plates anddiscs MC Manufacturer Rules

MC Rm >500N/mm² ≥M30 Manufacturer Rules

Bolts and tie rods

MC Alloyed orheat treated ≥M16 Manufacturer Rules

Nuts MC Rm >600N/mm² ≥M30 Manufacturer Rules

Forgings and castings MC Manufacturer Rules

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Table 6 Certification requirements for pressure equipment class II



Pressure equipment class II PC Society Rules

Plates, dished ends andheads MC Manufacturer Rules



Stays, stay bolts and staytubes MC Manufacturer Rules

Smoke tubes (tubes subjectto external pressure) MC Manufacturer Rules



Flanges, nozzles andbranches MC Manufacturer Rules

Manhole, headhole andhandhole closures MC Manufacturer Rules

Reinforcement plates anddiscs MC Manufacturer Rules

MC Rm >500N/mm² ≥M30 Manufacturer Rules

Bolts and tie rods

MC Alloyed orheat treated ≥M16 Manufacturer Rules

Nuts MC Rm >600N/mm² ≥M30 Manufacturer Rules

Forgings and castings MC Manufacturer Rules

Table 7 Certification requirements for pressure equipment class III



Pressure equipment class III PC Society Rules

Plates, dished ends andheads TR Manufacturer Rules


TR Manufacturer Rules

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Stays, stay bolts and staytubes TR Manufacturer Rules

Smoke tubes (tubes subjectto external pressure) TR Manufacturer Rules


TR Manufacturer Rules

Flanges, nozzles andbranches TR Manufacturer Rules

Manhole, headhole andhandhole closures TR Manufacturer Rules

Reinforcement plates anddiscs TR Manufacturer Rules

TR Rm >500N/mm² ≥M30 Manufacturer Rules

Bolts and tie rods

TR Alloyed orheat treated ≥M16 Manufacturer Rules

Nuts TR Rm >600N/mm² ≥M30 Manufacturer Rules

Forgings and castings TR Manufacturer Rules

Table 8 Certification requirements for equipment, valves and fittings



PC

PN

(pressure/temperature

rating)

DN >100mm and

PN >16 barSociety Pt.4 Ch.6Sec.9 [3]

PC

PN

(pressure/temperature

rating)

DN ≤100 mmor PN ≤16 bar Manufacturer

Pt.4 Ch.6Sec.9 [3]

PC

>120°C anddesigned for

a specificpressure/

temperaturecombination

DN >100mm and

PN >16 barSociety Sec. 7 [4.6.7]

Equipment, valves and fittings

PC

>120°C anddesigned for

a specificpressure/

temperaturecombination

DN ≤100 mmor PN ≤16 bar Manufacturer Sec. 7 [4.6.7]

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Boiler safety valves PC Society

— PN: nominal pressure— DN: nominal diameter

Table 9 Certification requirements for burners



Burner PC Society Rules

Fuel oil pre-heater PC Society Rules

Fuel oil cooler (MGO) PC Society Rules

Pipes and tubes TR Manufacturer Rules

Fittings TR Manufacturer Rules

Equipment for alarm andsafety action PC Society Rules

Table 10 Certification requirements for control, monitoring and safety systems


Issued by Certificationstandard*

Boiler control, monitoring andsafety system PC Society

Thermal oil heater control,monitoring and safety system PC Society

Oil fired water heater control,monitoring and safety system PC Society

*Unless otherwise specified the certification standard is the Society's rules

3.2.3 Gas cylinders for fixed fire extinguishing systems shall be delivered on board with a product certificateof the Society or with a certificate issued by a recognised certification authority according to nationalregulations based on the requirements of the design standard and marked accordingly π, UN or DOT.

3.2.4 For general requirements for certification, including definition of the certificate types, see Pt.1 Ch.3Sec.4 and Pt.1 Ch.3 Sec.5.

4 Accumulators for hydraulic systems

4.1 Design

4.1.1 The accumulators shall be designed according to a recognised international code accepted by theSociety, e.g. EN-14359, ISO 11120 or ISO 9809.The information or documentation, as required by the standard, shall be submitted for approval.

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4.1.2 Corrosion allowance shall not be less than 1 mm for accumulators made from ferrous materials.

4.2 Fabrication

4.2.1 The accumulators shall be made by a manufacturer approved by the Society for pressure equipmentclass I and II.The accumulators shall be manufactured to the same standard which form basis of the design.All forming, heat treatment, prototype testing and product testing shall meet with the requirements of thesame standard.The certification of the materials shall be in accordance with Table 5, Table 6 or Table 7 Certificationrequirements for pressure equipment.

4.3 Certification

4.3.1 The accumulators shall be certified by the Society. The Society’s product certificate will be issued aftercompletion of the testing as specified in the standard.

5 Gas cylinders for fixed fire extinguishing systems

5.1 General

5.1.1 Gas cylinders under this section are defined to be mass produced seamless or welded transportablerefillable pressure vessels used in fixed fire extinguishing systems.

5.1.2 Mass produced gas cylinders certified as part of a batch which are π, UN or DOT marked will beaccepted for fixed fire extinguishing systems on condition the approval, manufacturing and testing procedureof the applied standard is fully complied with.

5.2 Design

5.2.1 The gas cylinders shall be designed according to a recognised international standard accepted by theSociety, e.g. EN14208, EN13322, ISO 9809 or CFR 49.

5.2.2 The approval of the design shall be based on the design requirements and approval process asspecified in the applied standard.

5.3 Fabrication

5.3.1 The gas cylinders shall be manufactured to the same standard which form basis of the design.All forming, heat treatment, prototype testing and product testing shall meet with the requirements of theapplied standard.

5.4 Certification

5.4.1 The gas cylinders shall be delivered on board with a product certificate according to [3.2.3].

5.4.2 When certified by the Society the design shall be approved on case by case basis or by an obtainedtype approval.

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5.4.3 When certified by a recognised certification authority according to national regulations the gascylinders shall be documented by means of certificates identifying the serial no. of each cylinder. Thecertificates shall be made available to the attending surveyor.

6 Operating instructions and signboards

6.1 General

6.1.1 Manufacturers of pressure vessels, boilers, hot or warm water generators, thermal oil heaters, oilfiring equipment etc. shall supply operating and maintenance instructions and manuals together with theequipment.

6.1.2 An easily legible signboard shall be mounted at the control platform giving the most importantoperating instructions for boilers, hot or warm water generators, thermal oil heaters, oil firing equipment etc.

6.1.3 At the operating station for the oil burner a readily visible signboard shall be placed with the followinginstructions:

CAUTION!NO BURNER TO BE FIRED BEFORE

THE FURNACE HAS BEEN PROPERLY PURGED

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SECTION 2 MATERIALS

1 Material requirements

1.1 General

1.1.1 Materials for pressure equipment together with their valves, fittings, etc. shall meet the requirementsgiven in the relevant chapters and sections for pressure equipment in Pt.2 Ch.2.

Guidance note:The traditional stainless steels, including type 316 or 316L, should not be considered suitable for use in seawater systems.However, certain stainless steels with higher contents of chromium, molybdenum and nitrogen have improved resistance tolocalised corrosion. These steels include high molybdenum austenitic steels and ferritic austenitic (duplex) steels. Even these steelscannot be immune to attack under all situations; avoidance of stagnant seawater conditions and removal of welding oxides aresome of the important factors to the successful use.


1.1.2 The materials used shall have certificates according to Sec.1, Table 5 to Table 8.

1.2 Boilers and pressure vessels

1.2.1 Rolled steels for boilers and pressure vessels shall comply with the specifications given in Pt.2 Ch.2Sec.3.Fully killed and fine grain, normal strength structural steels complying with the specifications given in Pt.2Ch.2 Sec.2 will, however, be accepted for end plates for plate heat exchangers and the following class IIIpressure equipment:

— pressure vessels intended for water or non-flammable hydraulic liquids if the fluid temperature is less than95°C

— other pressure vessels where

where:

pd = design pressure

Do = outside diameter

1.2.2 The steel grades VL 360-0A, 410-0A and 460-0A will be accepted only for pressure equipment class IIand III with a material thickness of maximum 25 mm.

1.2.3 Steel grades complying with recognised national or international standards with chemical compositionand mechanical properties differing from the specifications referred to above, and with minimum specifiedtensile strength not exceeding 550 N/mm2, may be accepted subject to approval in each case. In such casesthe values of the mechanical properties used for deriving the allowable stress shall be subject to agreementby the Society.

1.2.4 Materials for pressure equipment designed for material temperatures below 0°C are subject toapproval in each case.

1.2.5 Grey cast iron is in general not to be used for the following:

— class I and II pressure equipment

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— class III pressure equipment where:

— pressure vessels containing toxic fluids and fluids with a flash point below 100°C.

pd = design pressure

Do = outside diameter

However, for bolted heads, covers or closures not forming a major part of the pressure equipment, grey castiron may be used for pd ≤ 10 bar.The use of grey cast iron in economisers will be subject to special consideration.

1.2.6 Nodular cast iron of the ferritic/pearlitic and pearlitic type is in general subject to the limitation of useas grey cast iron as specified in [1.2.5].

1.2.7 Nodular cast iron of the ferritic type with specified minimum elongation of 12%, shall not be used fortemperatures exceeding 350°C.

1.3 Thermal-oil heaters

1.3.1 Tubes and pipes for thermal-oil heaters shall be seamless steel tubes and pipes or welded steel tubesand pipes which are approved as equivalent to seamless types.

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SECTION 3 ARRANGEMENT

1 General

1.1 Access and inspection openings

1.1.1 Pressure equipment shall have openings in sufficient number and size for internal examination,cleaning and maintenance operations such as fitting and expanding of tubes.

1.1.2 For size, number, type and location of openings see App.A.

1.1.3 Detachable ends or covers and suitably located, removable pipe connections may be used as inspectionopenings.

1.1.4 All drums, headers and other large components of boilers shall be provided with openings, adequate innumber and size, to allow access for fabrication, cleaning and internal inspection.

1.1.5 Shell boilers with a shell diameter of 1400 mm or greater shall be designed to permit entry of a personand shall be provided with a manhole for this purpose.Also boilers with a shell diameter less than 1400 mm which are capable of being entered by a person shall beprovided with a manhole. Boilers with a shell diameter between 800 mm and 1400 mm shall be provided witha headhole as a minimum requirement.

1.1.6 Special consideration shall be taken to the accessibility for inspection of welded connections subjectedto high bending stresses, e.g. corner welds between flat plates and cylindrical shells or furnaces andattachment welds of stays.In case of circumferential corner welds not more than one single length equal to half the shell diameter, ora number of lengths totalling one shell diameter are hidden by tube nests, handholes for inspection of weldsare sufficient.

1.1.7 In all cases it shall be possible to inspect the bottom of the shell and the longitudinal welds. Handholesare sufficient for the inspection of the boiler’s lower endplate in case of vertical shell boilers.

1.1.8 Fired boilers including exhaust gas heated boilers/economisers shall be fitted with adequate numberand size of openings and facilities for internal inspection and cleaning of the flue gas and exhaust gas side.

1.2 Draining and venting

1.2.1 All pressure equipment shall be capable of being depressurised and completely emptied or drained.Particular attention shall be given to the adequate drainage of compressed air vessels.

1.2.2 Suitable connections for the execution of hydraulic pressure tests and a vent at the uppermost pointshall be provided.

1.3 Positioning

1.3.1 Pressure vessels, boilers and heaters shall be installed on foundations of substantial strength and insuch a position that there is sufficient access for cleaning, examination and repair anywhere on the outside.

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1.4 Marking

1.4.1 Each pressure equipment shall be permanently and legibly marked on the pressure part or on anameplate permanently attached to a principal pressure part to show its identity and origin.

1.4.2 The marking of pressure vessels shall show at least the following particulars:

— manufacturer's name and address— type designation and serial number— year of manufacture— maximum allowable working pressure— hydrostatic test pressure.

1.4.3 The marking of boilers shall show at least the following particulars:

— manufacturer's name and address— type designation and serial number— year of manufacture— maximum allowable working pressure— hydrostatic test pressure— allowable steam production for steam generators— maximum allowable temperature of super-heated steam provided that the steam generator is fitted with a

super heater with no shut-off capability— maximum allowable discharge temperature for hot water generators— maximum allowable heating power for hot water generators.

1.4.4 The marking of thermal oil heaters shall show at least the following particulars:

— manufacturer's name and address— type designation and serial number— year of manufacture— maximum allowable heating power— maximum allowable working pressure— maximum allowable discharge temperature— minimum flow rate— liquid capacity.

1.4.5 The marking of thermal oil expansion vessels and deaerator vessels shall show at least the followingparticulars:

— manufacturer's name and address— type designation and serial number— year of manufacture— maximum allowable working pressure— maximum allowable working temperature— capacity.

For expansion vessels with an open connection to the atmosphere, the maximum allowable working pressureshall be shown on the nameplate as "0" or "Atm.", even though a gauge pressure of 2 bar is taken as thedesign basis.

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2 Boilers

2.1 Instruments

2.1.1 All oil-fired boilers shall be provided with instrumentation permitting local surveillance.

2.2 Positioning

2.2.1 The clearance between boiler with uptake and tanks for fuel oil, lubricating oil and cargo oil and cargohold bulkheads shall be adequate for free circulation of air to keep the temperature of the oil well below theflashpoint and to avoid unacceptable heating of the cargo.Alternatively the tank surfaces and bulkheads shall be insulated.

Guidance note:The following clearances are considered to be sufficient:

— Distance between fuel oil tanks or hold bulkheads to:

— flat surfaces of boilers and uptakes: 500 mm

— cylindrical surfaces of boilers and uptakes: 300 mm.

— Vertical distance from top of boiler to nearest deck: 1300 mm.

— For watertube boilers, distance between the tank top and the underside of the bottom of the combustion chamber space: 750mm.


2.2.2 If oil-fired boilers are placed in the engine casing or in the funnel, the arrangements shall be such thatoil spray, in the case of leakage, will be intercepted and will not reach heated surfaces beneath. Coamings forstairs, pipe openings, etc. shall be of ample height.Platforms shall be fitted with sufficient drains to a waste-oil tank in the double bottom. These drains shall befitted in addition to those specified for drip trays of oil tanks and fuel-oil pump units.

2.3 Exhaust gas boiler or economisers2.3.1 Circulation systemsOne stand-by pump is required when forced circulation is necessary for operation of the boiler or economiser.

2.3.2 Soot-cleaning arrangementWater tube exhaust gas boilers or economisers of a design where soot deposit may create a problemregarding fire hazard, e.g. exhaust gas boilers with extended surface tubes shall have a soot-cleaningarrangement for use in the operation mode. In such cases, the soot cleaners shall be equipped withautomatic start and arranged for sequential operation and possibility for manual over-ride.

Guidance note:For extended surface tubes, soot deposits may create a problem when exhaust gas velocity is less than 12 m/s at normal operatingcondition.


Exhaust gas collecting pipes shall be provided with drain. The drainage system shall be capable of draining allwater when the water washing or water fire extinguishing system in the exhaust gas boiler or economizersare in operation.Necessary protection shall be made, so that water cannot enter into any of the engines.The drainage shall be led to a tank of suitable size.

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3 Components and equipment in thermal-oil installations

3.1 General

3.1.1 The main inlet and main outlet pipes for thermal-oil at the oil fired heater and at the heater heatedby exhaust gases shall have stop-valves, arranged for local manual and remote controlled operation from aneasily accessible location outside the heater room.

3.1.2 The heater shall be capable of being drained and ventilated as well from the position outside theimmediate area in which the heater is installed.

3.1.3 The heater regulation and the burner management shall be capable of ensuring that, under alloperating conditions, the thermal-oil temperature at no place in the heater will exceed a temperature whichwould cause an unacceptable rate of deterioration of the thermal-oil.

3.1.4 The plant arrangement shall ensure that the temperature of thermal-oil coming into direct contact withair will be below 50°C in order to prevent excessive oxidation.

3.1.5 Copper and copper alloys, which lead due to their catalytic effect to an increased ageing of the thermaloil, shall be avoided or oils with specific additives shall be used.

3.1.6 An expansion vessel shall be placed at a high level in the system. The space provided for expansionshall be such that the increase in the volume of the thermal oil at the maximum thermal oil temperature canbe safely accommodated. The following shall be regarded as minimum requirements: 1.5 times the increasein volume for volumes up to 1000 litres, and 1.3 times the increase for volumes over 1000 litres. The volumeis the total quantity of thermal oil contained in the system up to the lowest liquid level in the expansionvessel.

3.1.7 The expansion tanks shall have overflow pipes leading to the collecting tank.

3.1.8 Fast gravity discharge of the oil into a separate collecting tank shall be possible.

3.1.9 Heaters, expansion tank and pressure vessels in thermal oil systems shall be fitted with meansenabling them to be completely drained.

3.1.10 Sensors for the temperature measuring and monitoring devices shall be introduced into the systemthrough welded-in immersion pipes.

3.1.11 Grey cast iron is unacceptable for equipment items in the hot thermal oil circuit and for safety valves.

3.1.12 Notices shall be posted at the control stations of the circulating pumps stating that the pumps shallbe in operation at least for 10 minutes after stop of burners.

3.2 Heaters

3.2.1 The furnace of the oil-fired thermal oil heater shall be fitted with an interface to a fixed fire-extinguishing system. Manual release shall be arranged locally and remote controlled.

3.2.2 The thermal-oil heater heated by exhaust gases shall be fitted with interfaces to a fixed fireextinguishing and a cooling system. A drenching system providing at least 5 ltr/m²/min of water may beaccepted.

3.2.3 Soot cleaning arrangements shall be fitted in accordance with [2.3].

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3.2.4 The exhaust gas intake shall be arranged in a way that the thermal oil cannot penetrate the engineor the turbocharger in case of a leakage in the heater, fire extinguishing or the cleaning medium cannotpenetrate during heater cleaning, respectively. The drain shall be led to a suitable location.

3.2.5 The heater shall be so designed and installed that all tubes may be easily and readily inspected forsigns of corrosion and leakage.

3.2.6 Oil fired heaters shall be provided with inspection openings for examination of the combustionchamber.

3.2.7 Heaters heated by exhaust gas shall be provided with manholes serving as inspection openings at theexhaust gas intake and outlet.

3.2.8 The thermal-oil heater shall be arranged with the possibility for bypassing the exhaust by means ofdamper(s).The dampers will not be accepted as a means for controlling the temperature of the thermal-oil heaters.The bypass may be internal or external to the heater. In either case, the arrangements shall be such that fireextinguishing in the heater is possible without stopping the propulsion of the vessel.

Guidance note:For heaters with smooth surface heater tubes. Temperature control by means of exhaust gas dampers may be accepted on thecondition that it can be shown that a minimum gas velocity of 12 m/s through the heater is maintained, throughout the controlrange.


3.3 Expansion tank

3.3.1 All vessels, including those open to the atmosphere, shall be designed for a pressure of at least 2 bar,unless provision has to be made for a higher working pressure. Excepted from this requirement are tanksdesigned and dimensioned according to Hull Structures Pt.3

3.3.2 The dimensions of the expansion, overflow, drainage and venting pipes shall be applied according toTable 1.

Table 1 Nominal diameter of expansion, overflow, drainage and venting pipes depending on theoutput of the heater

Heater Output [kW]Expansion and overflow pipes

Nominal diameter DN

Drainage and venting pipes

Nominal diameter DN

≤ 600 25 32

≤ 900 32 40

≤ 1200 40 50

≤ 2400 50 65

≤ 6000 65 80

3.3.3 The quick drainage valve shall be arranged for remote control from the machinery central controlposition.

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3.4 Pre-pressurised systems

3.4.1 Pre-pressurised systems shall be equipped with an expansion vessel which content is blanketed with aninert gas. The inert gas supply to the expansion vessel has to be guaranteed.

3.4.2 The pressure in the expansion vessel shall be indicated and safeguarded against overpressure.

3.4.3 A pressure limiter shall be provided at the expansion vessel which gives an alarm and shuts-down andinterlocks the oil burner at a set pressure below the set-pressure of the safety valve.

3.5 Safety arrangements

3.5.1 Each heater shall be equipped with at least one safety valve having a blow-off capacity of at leastequal to the increase in volume of the thermal oil at the maximum heating power. During blow-off thepressure shall not increase above 10% over the maximum allowable working pressure.

3.6 Control and monitoring system

3.6.1 Circulation pumps and heater burners shall be arranged for start and stop from the local control paneland remote stop from an easily accessible location outside the thermal-oil heater room.

3.7 Insulation and shielding

3.7.1 All insulation shall be covered with an outer barrier, which shall be impervious to liquid. In areas andlocations where pipes may be exposed to mechanical impact, the outer barrier shall be made of galvanisedsteel plates or aluminium plates of sufficient impact strength to resist deformations from normal wear andstrain.

4 Oil burner and oil firing equipment

4.1 General

4.1.1 The type and design of the burner and its atomizing and air turbulence equipment shall ensurevirtually complete combustion of different liquid fuels intended to be burnt.

4.1.2 Equipment used, especially pumps and shut-off devices, shall be suitable for the particular applicationand for the fuel oils in use.

4.1.3 Oil burners shall be designed, fitted and adjusted in such a manner as to prevent the flame fromcausing damage to the surfaces or tubes of the heat generator which border the combustion space. Parts ofthe heat generator which might otherwise suffer damage shall be protected by refractory lining.

4.1.4 The firing system shall be arranged as to prevent the flame from blowing back into the boiler or engineroom and to allow unburned fuel to be safely drained.

4.1.5 Observation openings shall be provided at suitable points on the heat generator or burner throughwhich the ignition flame, the main flame and the lining can be observed.

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4.1.6 Every burner shall be equipped with an igniter. The ignition shall be initiated immediately after purging.In the case of low-capacity burners of monoblock type (permanently coupled oil pump and fan) ignition maybegin with start-up of the burner unless the latter is located in the roof of the chamber.

4.1.7 Where burners are blown through after shut-down, provision shall be made for the safe ignition of theresidual oil ejected.

4.1.8 Burners, which can be retracted or pivoted, shall be provided with a catch to hold the burner in theswung out position. Additionally the requirement according to Sec.6 Table 6 shall be observed.

4.2 Fuel oil supply

4.2.1 By means of a hand-operated quick-closing shut-off device mounted at the fuel oil manifold it shall bepossible to isolate the fuel supply to the burners from the pressurized fuel lines. Depending on design andmethod of operation a quick-closing shut-off device may also be required directly in front of each burner.

4.2.2 The equipment for fuel oil preheating shall enable the heat generator to be started up with the facilitiesavailable on board.

4.2.3 Where only steam-operated pre-heaters are present, fuel which does not require preheating has to beavailable to start up the burner.

4.2.4 Any controllable heat source may be used to preheat the fuel oil. Preheating with open flame is notpermitted.

4.2.5 If electric pre-heaters are applied, the requirements according to Ch.8 Sec.8 [1.3.7] apply.

4.2.6 Temperature or viscosity control of the fuel shall be done automatically. For monitoring purposes, athermometer or viscosimeter shall be fitted to the fuel oil pressure line in front of the burners.

4.2.7 The fuel oil supply temperature shall be selected so as to avoid excessive foaming, the formation ofvapour or gas and also the formation of deposits on the heating surface.

4.2.8 Fuel oil circulating lines shall be provided to enable the preheating of the fuel oil prior to the start-up ofthe heat generators.

4.2.9 When a change is made from heavy to light oil, the light oil shall not be passed through the heater orbe excessively heated (alarm system).

4.2.10 Ignition of burners shall take place at reduced fuel oil supply. Fuel oil shall not be supplied beforeignition device produces sufficient energy for safe ignition.

4.2.11 For steam-atomising burners and when steam blowing is used for cleaning of the burners, effectiveprecautions shall be taken in order to prevent fuel oil from penetrating into the steam system.

4.3 Combustion air supply

4.3.1 The boiler or heater shall ensure a sufficient air supply during all working conditions.

4.3.2 During all normal operating conditions, the air/fuel ratio and the air distribution between burners shallbe such that a reliable and nearly complete combustion takes place.

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4.3.3 Before ignition of first burner, the boiler shall be purged to such an extent that air quantity through theboiler is at least the greater of:

— three times the volume of the flue gas (from the burner to the chimney), or— five times the furnace volume of the boiler.

This condition is considered as satisfied if the pre-purge is carried out for 15 s, the amount of air being equalto the air flow corresponding to the nominal output of the burner.

4.3.4 Post-purge after stopping the last burner is advised. This operation does not, however, replace the pre-purge.

4.3.5 When the boiler is installed in the same room as other large air consumers (e.g. internal combustionengines or air compressors), ventilation shall be arranged so that no disturbance in the air supply to theboiler occurs.

4.3.6 Where an installation comprises several burners supplied with combustion air by a common fan, eachburner shall be fitted with a shut-off device (e.g. a flap). Means shall be provided for retaining the shut-offdevice in position and its position shall be indicated.

4.4 Exhaust gas ducting

4.4.1 Oil-fired boilers are in general not to have flaps or other arrangements which may interfere with thedraught in funnels or uptakes.

4.4.2 Dampers in uptakes and funnels should be avoided. Any damper which may be fitted shall be soinstalled that no oil supply is possible when the cross-section of the purge line is reduced below a certainminimum value. The position of the damper has to be indicated at the boiler control platform.

4.4.3 Where dampers or similar devices are fitted in the air supply duct, care has to be taken to ensure thatair for purging the combustion chamber is always available unless the oil supply is necessarily interrupted.

4.5 Marking

4.5.1 The following information shall be stated on a durable manufacturer’s name plate attached to theburner:

— manufacturer’s name plate— type and size— serial number— year of manufacture— min./max. oil flow— fuel oils to be used— degree of protection.

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SECTION 4 GENERAL DESIGN REQUIREMENTS

1 General

1.1 Application

1.1.1 The requirements in this section apply to pressure equipment under internal and external pressure andsubjected mainly to static loadings.

1.1.2 Where fatigue is considered to be a possible mode of failure, fatigue calculations may be required. Thecalculations may be carried out according to a recognised pressure equipment code accepted by the Society.

1.1.3 Pressure equipment subjected to external pressure, except furnaces, fireboxes and uptakes (see [7]),shall be calculated according to Pt.5 Ch.7 Sec.22 [2.4], the Society’s rules for underwater technology or arecognised international standard accepted by the Society.

1.1.4 Parts of pressure equipment not covered by these rules, e.g. flanges, bolts and tube plates in heatexchangers, end plates in plate heat exchangers or parts having geometrical properties outside the limitsof application of the calculating formulae, shall be designed and calculated according to a recognisedinternational code accepted by the Society.In general the nominal design stress shall not exceed that given in [2.5].The allowable stresses for the bolts shall be as specified in the recognised international code accepted by theSociety. The use of high strength materials shall be limited to grades lower than 12.9 of the metric gradessteel bolts.

1.1.5 The rules do not take into account thermal stresses. It is a condition for approval that the thermalstresses are accounted for by a sufficiently flexible construction and a sufficiently slow heating up and coolingdown period.In special cases an analysis of thermal stresses may be required

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Part 4 Systems and components Chapter 7 Pressure equipment · 2018. 1. 3. · P a r t 4 C h a p t e...

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